A pipetting device in the form of a small tube having a receptacle chamber and a first end with a discharge opening and a second open end is known in practice. One known pipetting unit is fabricated from plastic or glass. A suction device on the second, open end draws a liquid to be applied to a substrate into the receptacle through the discharge opening. The liquid to be applied can in turn be applied to a substrate or delivered into a reaction vessel. A sample of saliva or a similar substance can be added to the liquid to be applied can then be subjected to chemical or biochemical tests. The addition to the liquid of the substance to be analyzed takes place before the pipetting in a separate vessel.